Field of Invention
This invention relates to a hitch for a work machine, and more particularly to an adjustable link assembly for a hitch.
Description of Related Art
A work machine, such as an agricultural tractor, typically includes a coupling arrangement (sometimes referred to as a 3-point hitch) for attaching a work implement to the work machine. The coupling arrangement generally includes a link assembly for connecting an arm and a bar which extend outwardly from the frame of the work machine.
The link assembly includes an internally threaded sleeve and an externally threaded rod positioned within the internally threaded sleeve. The externally threaded rod meshingly engages the internally threaded sleeve so that relative rotation between these two elements in a first direction causes the externally threaded rod to be advanced out of the internally threaded sleeve thereby increasing the length of the link assembly. In the alternative, relative rotation between these two elements in a second direction causes the externally threaded rod to be advanced further into the internally threaded sleeve thereby decreasing the length of the link assembly. Adjusting the length of the link assembly in the above described manner is important for ensuring that the work implement is appropriately attached to the work machine.
Various devices have been utilized to address the problem of the length of the link assembly inadvertently changing during the use of the work machine. In particular, vibrations generated during use of the work machine are communicated to the internally threaded sleeve and the externally threaded rod through various work machine structures. These vibrations can cause relative rotation between the internally threaded sleeve and the externally threaded rod. As a result, the length of the link assembly inadvertently changes during use of the work machine which can adversely affect the performance of a work function.
In an attempt to address the aforementioned problem, some coupling arrangements include a locking mechanism 46 for preventing the relative rotation between the internally threaded sleeve and the externally threaded rod. However, a drawback to these types of latches is that they utilize a removable hair pin, lynch pin or other keeper. One problem that occurs is the field is that these pins that keep adjustment handle 78s in place are often lost. The present invention is directed to overcoming one or more of the problems as set forth above